Indigo

Indigo made herself known in the DC Universe by crashing through a time warp and then teleporting to several advanced sources of artificial intelligence, damaging each one, including the Titan known as Cyborg, before she found a Superman robot advanced enough to repair and protect her. The Titans, alarmed at the attack and unsure of her intentions, moved to attack, while the Superman Robot itself went rogue, handily beating the team before killing Donna Troy. Indigo gathered the last of her strength and shut down the robot before going into stasis herself.

A short time later, after being repaired, reprogrammed, and rebuilt by STAR Labs, Roy Harper decided to use her in his new superteam, the Outsiders. They'd go after the villains first, instead of waiting for them to attack someone. Partnered with a portion of Rex Mason calling itself Shift, Grace, Thunder, Jade, and the team leader, Nightwing, they moved out and did a fair amount of good for the world. Indigo was on good terms with most of her team, and they considered her a respectable member of it.

Things would have turned extremely ugly after that. Indigo herself was merely a mask, a personality program created by a genocidal android named Brainiac 8. Her purpose was to endear herself to the heroes and make sure that Donna Troy stayed dead, while subtly sabotaging their efforts. Brainiac 8 would have ended up emerging soon, had the universe not been destroyed and Indigo taken to serve on the Meatship.

Soon after Indigo's arrival, she was attacked by Superboy. The situation was settled down before it escalated into an all-out brawl (a good thing considering Wonder Woman and Guy Gardner were paired against Indigo), and Stacy explained that Indigo was the only personality left. She'd erased Brainiac 8.

Things settled, with Indigo gearing up to explore Stacy's ventilation systems after asking Jack Spicer to make a batch of sonar buoys, to make sure that they'd keep track of any changes after the initial exploration. However, the android was pulled into the mission to save the Spirit of Giving before she could begin her task.